Chapter 16: Immune System

Question 1

Innate Immunity

Answer 1

-natural
- only present in animals befroe exposure to pathogen
- 1st and 2nd line of defence
- fast
- nonspecific- chemical, internal cellular, external barriers

Question 2

Adaptive Immunity

Answer 2

• acquired
  -3rd line of defence
  -developed after exposure to pathogen
• slow and specific- humoral (extracellular fluid), cytotoxic (intracellular pathogens and cytokines- T cells)

Question 3

first line: physical factors (external defenses)

Answer 3

• skin and tightly packed cels (outer epidermis and keratin)
• mucous membranes (line the GI, respiratory, urogenital tracts
• ciliary escalatior- trapped and transport microbes away from lungs
• washing action: tears, saliva, urine and vaginal secretions

Question 4

first line: chemical factors (external defenses)

Answer 4

• secretions: skin pH 3-5 (inhibit microbes)
  -lysozyme (enzyme in skin, saliva, and tear secretions
• fungistatic fatty acid in sebum (oily skin)
• lactic acid bacteria in vagina
• stomach acid
  -normal microflora (antagonism, competitive)

Question 5

2 line of defense

Answer 5

1) defensive cells
2) inflammation
3) fever
4) antimicrobial substance

Question 6

defensive cells

Answer 6

• WBCs (leukocytes) engulf pathogens by phagocytosis
• phagocytic cells- engulf and destroy pathogens, act as antigen presenting cells (APCs)
• 3 major types of phagocytic cells: macrophages (circulating phagocytes), neutrophils (stimulate acquired immunity), dendritic cells (stimulates acquired immunity).

Question 7

phagocytosis

Answer 7

1) chemotaxis and adherance of phagocyte to microbe
2) ingestion of microbe by phaogcyte
3) formation of phagosome (phagocytic vessicle)
4) formation of phagosome with lysosome to form phagolysosome
5) digestion of ingested microbes by enzymes in the phagolysosome
6) formation of the residual body containing indigestable material
6) discharge of waste materials

Question 8

What are some ways that pathogens evade phagocytosis (virulence factors) (6)

Answer 8

1) M protein or capsule- prevention of adherance to macrophage ex. streptococcus pyogenes
2) leukocidins- kill macrophages ex. staphloccous aureus
3) lysis of phagolysosome ex. listeria monocytogenes
4) escape from phagosome
5) prevent fusion of phagosome with lysosome ex. HIV or M. tuberculosis
6) survive the phagolysosome ex. cotiella bunetti

Question 9

Second line: Inflammation

Answer 9

can be local or systemic
signs and symptoms of inflammation: redness, pain, heat, swelling (edema), and loss of function

Question 10

words used to explain the process of local inflammation

Answer 10

1) redness, swelling pain, heat, loss of function
2) vasodilation
3) mast cells
4) tissue repair
5) emigration
6) margination
7) macrophages
8) phagocytes
9) phagocytosis
10) neutrophils
11) histamine
12) pus

Question 11

second line: internal defenses

Answer 11

fever- raising the body temperature to help body fight infections
- systemi response (systemic inflammation)- abnormally high body temp

Question 12

second line: antimicrobial chemicals

Answer 12

1) interferons- inhibit viral multiplation secreted by viral infected cells
2) defensins- secreted by macrophages to destroy pathogens
3) complement system- proteins that attack and lyse microbes

Question 13

complement system is protective in 3 ways

Answer 13

1) opsonization- promotes attachment of phagocyte to microbe and enhances phagocytosis
2) cytolysis- complement proteins (MAC) punch holes in pathogen’s cell membrane which bursts cell. gram - are more susceptable
3) activation of inflammation- attracts phagocytes to the site of infection- chemotactic